1. Field of the Invention
The present invention relates to an agricultural tillage apparatus including rear press wheels, and more particularly, the invention pertains to an agricultural tillage apparatus that provides improved frame flexibility such that the rear press wheels can more closely follow the contours of the ground, that provides improved weight distribution for the rear press wheels, and that provides adjustable weight transfer to the rear press wheels.
2. Description of the Related Art
Typical agricultural seeders are wheeled implements which are towed by agricultural work vehicles such as tractors. A seeder has a frame structure which has containers for seeds and a number of seed insertion devices such as shank type seed drills. The seed drills are arranged in horizontal rows to provide uniform application of the seeds in rows in the soil. The seeder frame structure is supported by a number of wheels. Typically the frame structure has a number of front land wheels and rear press wheels. The rear press wheels stabilize the seeder and compact the soil over the planted seeds. Compaction immediately after planting is very beneficial to crop yields. When soil is packed around the newly-planted seed, moisture is retained in the soil by expelling the air in the soil. As a result, the seed does not dry out and can draw water up for growth.
Various seeding and/or compaction devices for packing the soil after tilling are known in the prior art. In these devices, separate land wheels are provided to support the implement (including the drills and rear press wheels) when raised for turning or transport to a different location. In operation, the drills and press wheels are lowered so that the rear press wheels track a path behind the drills to compact the soil.
Some known seeding and/or compaction devices suffer from uneven weight distribution on the land wheels and rear press wheels. This can cause seed insertion which is uneven and/or deeper or shallower than desired, and uneven soil compaction in seeded areas. U.S. Pat. No. 6,125,778 has proposed one solution to this problem by providing a seeder with a weight distribution system such that weight on the front wheels is distributed to the work vehicle via the tow hitch and the rear wheels.
Some known seeding and/or compaction devices are also disadvantageous in that the rear press wheels are unable to independently follow the contours of the ground. This can result in uneven compaction in tilled areas. U.S. Pat. No. 4,519,460 has proposed one solution to this problem by providing a tillage implement in which the rear press wheels are able to independently follow the contours of the ground.
While solutions has been proposed to the problems associated with uneven seed insertion and uneven soil compaction, there still exists a need for an improved agricultural tillage apparatus that provides rear press wheels that can more closely follow the contours of the ground, that provides improved weight distribution for the rear press wheels, and that provides adjustable weight transfer to the rear press wheels.